Windeck is a municipality in the Rhein-Sieg district, in North Rhine-Westphalia, Germany. It is situated on the river Sieg, approx. 35 km east of Bonn and 35 km west of Siegen. Many think the municipality is named after the ruined castle of Windeck but in fact the first place to hold the name was the village of Windeck which is now called "Old Windeck". Around that village other villages were founded and so Windeck now has about 20,000 inhabitants.